Advantages of locating the converter before the turbine of the boost unit

The article discusses the principles of operation of the catalytic neutralization system located in the exhaust path to the turbine of the diesel boost unit or gas engine. The important advantages of such a system are the high efficiency of reducing emissions of harmful substances in a wide range of loads and the possibility of using thermal energy of catalytic reactions in the operating cycle of a hybrid engine. Due to the increased neutralization efficiency, it is also possible to use catalytic reactors with a smaller core volume. The work on an experimental study of a new arrangement of the neutralization system was started in JSC “Scientific and Production Alliance “Turbotehnika”. The work is aimed at determining the possibility of regulating the power of the turbine using the heat flux of the neutralization system. To obtain the necessary thermal effect, it is proposed to use the supply of additional (secondary) fuel to the input of the catalytic converter. The oxidation of secondary fuel is provided by the presence of free oxygen in the exhaust gases of the engines during the combustion of lean mixtures. An additional regulation of the turbine power is designed to eliminate the known problems of a single-stage gas turbine pressurization, which is the lack of available exhaust energy in the low-speed region and the delay in the reaction to transient modes. The article presents the results of an experimental study of a prototype converter as part of an engine on a motor test bench. Confirmation of the possibility of additional control of the turbine was received. As a result of the research and testing, the features of the new design of the neutralization system, which provides for the combination of a converter with a turbocompressor in a single module, are identified. It is proposed to place a cellular toroidal catalytic unit in the cavity in front of the turbine coil.

nitrogen oxides, exhaust gas aftertreatment, pre-turbine catalyst